Chemicals and fertilizers are commonly applied to agricultural crops. Applicator implements for liquid chemicals and fertilizers commonly include a vehicle, usually self propelled, with a tank and a plurality of spray or ejection nozzles in fluid communication with the tank. Often, the nozzles are supported on a boom structure which extends perpendicularly outward on both sides of the implement. With the advent of my no-bounce positioning boom apparatus disclosed in U.S. patent application Ser. No. 160,677 filed June 18, 1980, boom lengths have almost doubled. As a consequence, situations are encountered wherein it would be advantageous to have a shorter boom, such as, the last swath along a field edge. Additionally, the super long booms are difficult to maneuver in a farm yard or to drive on a road. Since booms have heretofore been substantially shorter, however, there seems to be little applicable art with respect to making a boom shorter while at the same time retaining the capability of keeping it functional at the shorter length.
As a baseline, it is recognized that Chemical applicator implements are known to include cooperating booms extending perpendicularly outwardly from the sides of a tank-truck at the rear end thereof. Articulated booms having neither horizontal or vertical axis are known. These presently known folding booms, however, are intended primarily to make the boom more compact for transport. As indicated, it has been unnecessary, until the advent of the super-long booms, to provide a folding capability for the outer portion of the boom while keeping the inner portion of the boom extended and operational for chemical delivery.